All About Insulin Pumps

An insulin pump is a small external device, about the size of a pager that is programmed to deliver a slow, continuous infusion (basal dose) of short-acting insulin into the body. At mealtimes, the wearer programs a bolus dose to cover the carbohydrates in the food she is going to eat.

The pump itself consists of a reservoir for holding insulin, a digital display with dose and time information, and a port where the insulin leaves the unit. Most pumps are also designed with a piece of thin plastic tubing called an infusion set that hooks on to the pump and carries the insulin from the unit to the body. A flexible plastic cannula or a needle is inserted just under the skin to deliver the insulin.

Infusion sets must be changed every two to three days, and insertion sites rotated. Most people use the abdomen for insertion, although the same sites that can be used for insulin injection with a syringe can also be used for insertion.

A newer insulin pump called the OmniPod (from Insulet) forgoes the tubing and attaches the insulin source (a disposable insulin “pod”) directly to the cannula. A separate electronic device, called a personal diabetes manager (PDM), programs the insulin delivery and sends wireless signals to the pod. The PDM also doubles as a blood glucose meter and uses the results to help the user calculate insulin dosing.

The insulin pods last for approximately three days; they are waterproof and can be worn in the shower. They have an adhesive backing that firmly attaches to the skin around the cannula. However, once attached, the pods should not be removed until replacement, so they are not as easy to “disconnect” from as a traditional pump is.

An insulin pump administers insulin through a thin catheter in the abdominal fat to help control a person's blood sugar levels.

Who Pumps?

Children who crave added flexibility may prefer a pump. People with “brittle” diabetes may find the pump helpful as well, because they can't get a handle on large glucose swings. People who suffer from nighttime lows (and accompanying morning highs) may also find that the pump helps them improve control; pumps can be programmed to increase the basal dose as morning glucose levels start to rise (i.e., the dawn phenomenon).

And pumps are not just for type 1 diabetes patients. People with type 2 diabetes who are on insulin therapy may benefit from pumping too, particularly if they are having trouble achieving their A1C goals with regular injection therapy.

What are basal and bolus doses?

A basal dose is a slow, continuous infusion of small amounts of insulin that is designed to mimic the insulin secretion of a healthy pancreas between meals. A bolus is a larger dose of insulin taken before a meal to cover the resulting rise in blood glucose levels. The bolus is computed by calculating the carbohydrates contained in the meal.

An insulin pump requires a dedicated patient — or, in the case of a small child, a dedicated parent. It is not a “plug-and-play” solution to your diabetes. Blood glucose levels must still be tested at least four times daily, bolus doses for meals have to be computed and programmed, and infusion sets have to be changed regularly. But people who are willing and able to put in the effort often find that the pump gives them that elusive control that injections couldn't.

Practical Matters

Of course, being hooked up to a pump 24/7 does bring up all sorts of daily dilemmas. Following are a few pointers on pumps that may answer the more practical questions you may be asking yourself about pump therapy:

  • Many pumps are waterproof (to a point), or at the very least water-resistant. So if you accidentally get them wet, you're covered. There are also a variety of special waterproof and shock-resistant cases available.

  • Infusion sets come with tubing that is several feet in length. The extra length, which doesn't have to be used, comes in handy if you like to put your pump next to your bed at night, or even leave it out of the tub while you bathe or shower.

  • Pumps are worn to bed. Pumps keep working even when you're sleeping. Good places to keep your pump at night are under the pillow, in a pajama pocket, or on the nightstand.

  • Pumps can be discrete. If you don't feel comfortable wearing your pump like a beeper, there are many alternatives. Special pouches and straps are also available to wear pumps on the body under clothing.

  • Pumps can be disconnected, usually up to an hour. If you prefer to shower, swim, or have sex without the constant companionship of your pump, you can. Always check blood glucose levels when you hook back up.

Alert

Be sure to read the directions for use for your particular pump thoroughly to find out its full range of capabilities. Your doctor may also have special instructions regarding pump disconnection and other issues. A professional pump trainer (often a CDE) can be invaluable in getting you off on the right foot.

Insurance and Medicare Issues

An insulin pump is a major investment. Pumps run around $6,000 (some higher, some lower), plus the cost of infusion sets and other supplies, which can run several hundred dollars per month. The good news is that because tight control of glucose levels has been proved to reduce diabetes-related complications (in the DCCT and other trials), many insurance companies are more than willing to cover the price of a pump early, rather than pay the price of more expensive treatment for serious complications later.

Medicare will cover insulin pumps for both type 1 and type 2 diabetes patients, but they must meet strict clinical criteria to qualify. If you and your doctor think that you are a good candidate for the pump, work with him and his insurance coordinator to see if you meet Medicare guidelines.

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